class NoteTaker
  attr_reader :commentary

  def initialize(title)
    @commentary = [title]
  end

  def note(notation)
    @commentary << "Note: #{notation}"
  end
end

class TimingNoteTaker < NoteTaker
  def timestamp
    note(boundary("-"))
    @commentary << Time.now.to_s
  end

  def boundary(character)
    character * 20
  end
end

child = TimingNoteTaker.new("May 1")
child.timestamp
child.note("coffee")
child.note("bagels")
child.timestamp
child.note("email")
child.note("chat")
puts child.commentary